Coolant pumping device

ABSTRACT

A coolant pumping device includes a casing containing a stator portion of an electrical motor, including windings and silicon steel plates, and a control circuit board. A first chamber is formed atop the casing in which a blade assembly is rotatably received for effecting circulation of a coolant. A second chamber delimited by a cylindrical wall fixed inside the casing rotatably receives a rotor magnet, which is driven by the stator portion. The blade assembly is fixed to the rotor magnet. Slots are defined in the casing for retaining the control circuit board. A Hall IC, serving as a sensing element for detecting polarity of the magnet inside the second chamber is electrically connected to the circuit board and is fixed inside the casing. The sensing element provides a detection signal to the control circuit board to enhance operation smoothness of the pumping device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a coolant pumping device forcirculating coolant through a computer device, and in particular to acoolant pumping device comprising a sensing element for detectingpolarity of a rotor magnet to enhance operation smoothness of thepumping device.

2. The Related Art

A conventional coolant pumping device of the above-mentioned typecomprises a rotor magnet rotatably fit over an axle, which is driven bya stator portion comprising windings and silicon steel plates. The rotormagnet in turn drives the rotation of a blade assembly to effectcirculation of coolant.

The conventional coolant pumping device suffers a drawback that when themagnetic poles of the magnet are exactly opposite to the magnetic polesof the magnetic field induced by the windings, the rotor magnet becomesstationary and starting rotation of the rotor in such a condition isdifficult for the magnet is attracted by the magnetic field of thewindings and no repulsive force is induced between the magnet and thewindings. Starting the rotation of the rotor under such a condition isdifficult, and high level of noise can be generated. This in turn stopsthe circulation of the coolant through a computer device with which thepumping device is combined for cooling heat-generating elements orcomponents of the computer device. As a result, over-heating of thecomputer device may occur and failure of the operation of the computerdevice results.

Thus, it is desired to have a coolant pumping device that overcomes theproblem of starting as discussed above.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a coolant pumpingdevice that effectively overcomes the problem of starting occurring inthe conventional designs and enhances the operation smoothness of thepumping device thereby improving heat removal efficiency.

Another object of the present invention is to provide a coolant pumpingdevice comprising a sensing element for detecting the polarity of arotor magnet in order to enhance the operation smoothness of the pumpingdevice.

To achieve the above objects, in accordance with the present invention,there is provided a coolant pumping device, particularly suitable forliquid based cooling operation of computer devices, comprising a casingcontaining a stator portion of an electrical motor, comprising windingsand silicon steel plates, and a control circuit board. A first chamberis formed atop the casing in which a blade assembly is rotatablyreceived for effecting circulation of a coolant. A second chamberdelimited by a cylindrical wall fixed inside the casing rotatablyreceives a rotor magnet, which is driven by the stator portion. Theblade assembly/is fixed to the rotor magnet. Slots are defined in thecasing for retaining the control circuit board. A Hall IC, serving as asensing element for detecting polarity of the magnet inside the secondchamber is electrically connected to the circuit board and is fixedinside the casing. The sensing element provides a detection signal tothe control circuit board to enhance operation smoothness of the pumpingdevice.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be apparent to those skilled in the art byreading the following description of a preferred embodiment thereof,with reference to the attached drawings, in which:

FIG. 1 is a perspective view of a coolant pumping device constructed inaccordance with the present invention;

FIG. 2 is an exploded view of the coolant pumping device of the presentinvention;

FIG. 3 is a cross-sectional view of the pumping device of the presentinvention;

FIG. 4 is a perspective view showing a casing of the coolant pumpingdevice in an up-side-down manner to illustrate inside details thereof;and

FIG. 5 is a bottom view of the casing of the coolant pumping device ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the drawings and in particular to FIGS. 1 and 2, whichshow, respectively, a perspective view and an exploded view of a coolantpumping device constructed in accordance with the present invention,generally designated with reference numeral 10, the coolant pumpingdevice 10 comprises a casing 11 defining an interior space (not labeled)in which parts constituting a stator portion of an electrical motor arearranged, including at least windings 30 and silicon steel plates 31. Acircuit board 40 on which a circuit for controlling power supplied tothe stator portion is formed is also arranged inside the casing 10 andin electrical connection with the stator portion.

A first chamber 12 is formed atop the casing 11. In the embodimentillustrated, the first chamber 12 comprises a cylindrical outer wallfrom which a coolant outlet 18, which in the embodiment illustrated isin the form of a shaped tube in fluid communication with the firstchamber 12, extends. A lid 17 closes a top opening (not labeled) of thefirst chamber 12, preferably in a removable manner. A coolant inlet 16,also in the form of a tube, is formed on the lid 17 and in fluidcommunication with the first chamber 12. A second chamber 19 (FIGS. 4and 5), in communication with the first chamber 12, is delimited by acylindrical wall extending into the interior of the casing 11 and partlysurrounded by the silicon steel plates 31 of the stator portion. A fixedaxle 13 is concentrically formed in and co-extends along the secondchamber 19 with a top end extending into the first chamber 12.

Also referring to FIG. 3, a magnet 14 is received in the second chamber19 and is rotatably fit over the axle 13 to serve as a rotor of themotor. A blade assembly, 15 is arranged inside the first chamber 12 androtatably fit over the top end of the axle 13 and fixed to the magnet 14to rotate in unison with the magnet 14. Thus, when power is supplied tothe windings 30, a magnetic field is induced on the magnet 14 by thesteel plates 31, which drives the rotation of the magnet 14 and theblade assembly 15. The rotation of the blade assembly 15 inside thefirst chamber 12 draws coolant from the inlet tube 16 into the firstchamber 12 and drives the coolant out of the first chamber 12 throughthe outlet tube 18 to effect circulation of the coolant.

Also referring to FIGS. 4 and 5, which show an up-side-down perspectiveview and a bottom view of the casing 11 of the coolant pumping device 10of the present invention, respectively, a first retention slot 20 isformed on an outside surface of the cylindrical wall of the secondchamber 19. Also, second retention slots 21 are formed on oppositeinside surfaces of the casing 11 to respectively receive opposite edgesof the circuit board 40, thereby retaining the circuit board 40 insidethe casing 11. A sensing element 41, which is electrically connected toand spatially extending from the circuit board 40 (also see FIG. 2), isreceived and retained in the first retention slot 20, whereby thesensing element 41 is located at a position corresponding to the magnet14 inside the second chamber 19.

The sensing element 41 detects the polarity of the rotor magnet 14 andprovides control signal to the control circuit of the circuit board 40,which changes the magnetic field induced by the windings 30 to enhancedrivability of the rotor 14. For example, when the magnet 14 is at suchan angular position where the north pole of the magnet 14 opposes thesensing element 41 and where the rotor magnet 14 cannot be driven intorotation smoothly, the sensing element 41 reverses the magnetic field inshort period of time to drive the rotor 14 easily. This effectivelysolves the problem of undesired problems, such as delay and severevibration, in starting the rotation of the rotor that often encounteredin the prior art devices.

Any known sensing element 41 can be used in the coolant pumping device10 of the present invention provided such a sensing element 41 functionsas described above. An example of the sensing element 41 comprises aHall IC, which detects the polarity of the magnet 14 and providesdesired control signals to the circuit board 40.

To this end, it is obvious that the, present invention has a simpleconstruction, which is not much more complicated than the conventionaldevices, while effective in enhancing smoothness of rotation starting ofthe rotor. The cooling efficiency of the coolant pumping device of thepresent invention can thus be improved over the conventional devices,which is particularly of interest in the applications of heatdissipation for high efficiency computer systems. Computer systems withsuch a coolant pumping device can be operated more smoothly withoutundesired failure caused by over-heating.

Although the present invention has been described with reference to thepreferred embodiment thereof, it is apparent to those skilled in the artthat a variety of modifications and changes may be made withoutdeparting from the scope of the present invention which is intended tobe defined by the appended claims.

1. A pumping device comprising: a casing member encasing windings andsilicon steel plates, a circuit board being arranged in the casing forcontrolling supply of power; a first chamber formed atop the casing anddelimited by an outer wall from which an outlet is formed, the outletbeing in fluid communication with the first chamber, a lid removablyclosing a top opening of the first chamber and forming an inlet in fluidcommunication with the first chamber; a second chamber delimited by anouter wall arranged inside the casing, the second chamber being in fluidcommunication with the first chamber; a magnet rotatably received in thesecond chamber; a blade assembly fixed to and rotatable in unison withthe magnet, the blade assembly being rotatably positioned in the firstchamber for driving a fluid that enters the first chamber from the inletand that is discharged through the outlet; at least one circuit boardretention slot formed on an inside surface of a wall of the casing toreceive and retain the circuit board inside the casing; and a sensingelement in electrical connection with the circuit board, the sensingelement being received and retained in a sensing element retention slotformed on an outside surface of the wall of the second chamber tocorrespond in position to the magnet received in the second chamber. 2.The pumping device as claimed in claim 1, wherein the sensing elementcomprises a Hall IC.